To ensure the best chance for successful treatment for colon or rectal cancer, it is important to remove the entire tumor, using the most direct approach possible. That means some type of surgery. Other treatments, such as radiation therapy or chemotherapy, cannot replace surgery, although in some cases they may play an important role in the treatment process.
There are two types of surgical procedures:
Polypectomy – If the tumor is small and hasn’t invaded the layers of the colon, it is possible to remove (excise) just the tumor, without cutting all the way through (transecting) the bowel. The procedure is done with a flexible tube inserted through the anus. It is called local excision or polypectomy, and is used mostly for very early polyps and for early cancers in the rectum.
Segmental colectomy – If the tumor has begun to infiltrate—or spread—across the wall of the bowel, then the best option is to remove the section of the colon containing the tumor, together with a short piece of healthy bowel on either side, to make sure no cancer cells are left behind. This procedure is done surgically, through the wall of the abdomen and is called a partial colectomy, or segmental colectomy.
POLYPECTOMY or LOCAL EXCISION
Tumors that have not spread beyond the inner layers of the bowel lining (mucosa), can sometimes be treated without major surgery. There are two ways to perform the local excision: In case of colon tumors (polyps), the physician can remove them with a sigmoidoscope or colonoscope (the same devices that are used to view the colon lining during a diagnostic examination) without cutting through the colon or through the abdominal wall. This procedure is called a local excision or polypectomy. For rectal polyps, or some very early rectal cancers, a colorectal surgeon can remove the tumor and a margin of healthy tissue by operating through the anus. This is called a transanal resection.
Because it is so important to eliminate all of the cancerous tissue, local resection is not an option for treating cancers that cannot be completely removed with this procedure. Your physician will consider the cancer’s size and its exact location, and review the biopsy results to decide whether a local resection is the right choice for you.
To ensure the speedy completion of the procedure, it is important that your bowel is as clean as possible. If you had a colonoscopy before, you are already familiar with the bowel preparation, or “prep.” Specific prep instructions vary from physician to physician. More than likely, you’ll need to be on a clear liquid diet for a short time. That means no solid foods, and not even milk. Broth and Jell-O are acceptable. The night before the procedure you will take a potent laxative, followed by a large amount of fluids. You will probably finish off with an enema on the morning of your surgery. In some cases, this step is not done. It is imperative that you follow the instructions given to you. A poorly cleaned colon may require the procedure to be postponed.
You’ll also be asked to sign an informed consent form as an indication that you understand the procedure and the possible complications, such as infection and bleeding. Read the form carefully and ask for explanations of any parts that you are not comfortable with. A local excision can be done in an outpatient surgicenter or in a hospital.
When you arrive at the facility, you may be given additional enemas to complete the cleaning of your colon. You will be asked to remove dentures or glasses. If you wear contact lenses, make arrangements for their safekeeping. Do not wear makeup or jewelry on the day of your procedure.
A polypectomy may be done by a gastroenterologist (a doctor who specializes in diagnosing and treating diseases of the digestive tract) or by a colorectal surgeon. The actual removal of the lesion itself is painless because the bowel nerves are only sensitive to stretching. You will be given medication to make you drowsy and comfortable, and you probably won’t even remember much about the procedure.
You will be positioned comfortably on your side, with your knees slightly bent. The physician will insert the colonoscope into your anus, and using a TV monitor will gradually advance the instrument up the colon, carefully examining the wall as the tube travels upward. When the tip of the colonoscope reaches the suspect area, the physician will identify and remove the polyp.
If the lesion is shaped like a mushroom, the excision is done by passing a wire snare down the colonoscope, looping it around the stalk, and tightening the snare. Then an electric current is passed through the wire. This coagulates the blood vessels and cuts through the stalk. After removal, the polyp is sent to the pathology laboratory for microscopic examination.
If the cancer is a superficial lesion (shaped like a mound, rather than the usual mushroom), the physician will use other tools to remove the cancerous tissue from the surface of the bowel, being careful not to leave cancerous cells behind.
For select, very early rectal cancers, your surgeon may recommend a transanal excision. Transanal excision involves cutting through layers of the rectum to remove the cancer, as well as some of the surrounding normal rectal tissue. The procedure can be done through the anus, and leaves the rectum itself intact.
After the Procedure
Following a polypectomy, you will remain in the recovery area for about an hour. The length of time you will be at the clinic varies for each patient. It depends on the bowel preparation, the procedure and your recovery time. The average procedure and recovery time is about two hours.
Your doctor will discuss the results of your examination before you leave the recovery room. You may want a family member present when the doctor discusses these results, since your memory might still be affected by the medication you received prior to the procedure.
You will be given specific instructions to follow, and a list of symptoms for which you should call the physician. Because it may take a while for you to be fully awake enough to drive a car, you will need a friend or relative to accompany you to the hospital to drive you home after the procedure.
If you have a transanal excision, your recovery and discharge may be different from what you could have expected if you had a polypectomy. A transanal excision is often performed in a hospital, under general anesthesia, rather than under local sedation. Depending on the extent of the excision and your health, you may need to stay one or more nights in the hospital.
If your tumor is removed by either polypectomy or transanal excision, it is very important to remember that depending upon what the final pathology report says, your physicians may recommend further treatment, such as radiation therapy, chemotherapy, or more extensive surgery.
As with any surgical procedure, there are risks associated with local excision and polypectomy. Before surgery, your physician will describe to you in detail the complications that are possible given your particular health situation.
One possible but rare complication of local resection is perforation of the bowel. This may require open surgery, probably through the wall of the abdomen. Sometimes there is prolonged bleeding from the excision site, but the bleeding generally stops with no additional surgery. In any case, don’t hesitate to call your physician if you experience any symptoms that you didn’t expect.